Humor Me with Your Thoughts on This Series of Screen Filters to Manage Fines

Let's start with pond water going thru a settlement chamber going thru a static K1 bed. Coming out of the K1 filter, the water passes through a series of screens, each one progressively finer than the previous one. These screens aren't the expensive wedge-wire sieves, but are the regular stainless steel screens easily found in hardware stores. Each screen size come in pairs, so that the dirty screen can be pulled out and quickly replaced by the clean one. Later on, an offline cleaning can be done on the dirty screen using a pressure washer.

How many screens would you put in ? What would be the starting size (in microns) of the coarsest first screen? What would be the next? And next? And the last?

Yes, this idea is crude, I admit. It's too simple and lacking in sophistication. But I was hoping that by having different levels of screening, the finest and last screen won't clog up as quickly if there were just one fine screen. And by trial and error, I could find a set of screens that would be manageable for me. For example, if I went with a very fine last screen, I may find myself cleaning too often for my taste, and I would have to choose a coarser last-stage screen.

I am thinking of a 4-stage screen filtering setup. Starting from 2400 microns, then 1200 microns, then 600 microns, then 300 microns. What are your thoughts?

A few years back I built a progressive ss screen prefilter that worked ok. After three years I replace it with a Zakki sieve. 2-1000 micron 1 500 micron and 1 9 sometines 2) 250 micron. Could go just about 7 days on a bd circuit at 3000 gph.

Thanks for sharing creeekds. If that setup can go for a week between cleaning, its really not bad at all. 250 microns at that. Is there a reason for having 2 1000-microns screens? Since my flowrate is around 2500 gph with a feed load of 350g/day, would appreciate if you could give me your feed rate.

I changed from static K1 in Nexus, to Cetus to US3. IMHO, sieves deliver more uniform, predictable mechanical filtration to a smaller particle size. Sieves are basically self clean where static barrios, like K1 or a traditional screen, are not. With a barrier, the resistance to flow increases over time. With a sieve the captured particles slide dow the parabolic curve and out of the area where the water continues to flow unimpeded. I will take a sieve over a static barrier any day. But a static barrier beats the heck out of letting unfiltered water dump detritus on the media where you are trying to grow conversion bacteria.

Thanks for sharing creeekds. If that setup can go for a week between cleaning, its really not bad at all. 250 microns at that. Is there a reason for having 2 1000-microns screens? Since my flowrate is around 2500 gph with a feed load of 350g/day, would appreciate if you could give me your feed rate.

Why did you change to a Zakki sieve?

The reason for two 1000 micron screens, was because AES sent me 2 1/2 times what I ordered.(end of roll) So I decided to cut up the white barrel which was the support of the screen system, and line it with 1000 micron screen....more is better ??
The Zakki takes about thirty seconds to clean.

Also had this design that I did not build. But it could be cleaned with a hose, removing each section as they are cleaned pushing the waste down into the waste line.

1000 micron is about the size of screens on most home windows. It will catch relative large bits of algae plus leaves...etc. Indeed you do want something much finer behind it. If you have the screen, do put in two layers. The second layer will catch something. I think around 300 micron is about as fine as practical without some self cleaning mechanism such as the parabolic cure of a sieve or the backwash pump of an RDF. I know that when I had the Answer, not that takes me back over 10 years, it would implode in a heartbeat if the backwash pump stopped or in you let bio film clog the 100 micron screen.

I would agree. But I would want two for redundancy. And for many in the hobby, the cost of RDFs is still prohibitive. But if cost is not the limit, it is very hard to beat an RDF that feeds a shower.

To me the next best thing to an RDF is a sieve. Again not cheap, but significantly less cost than an RDF. I think the set below a sieve is some type of barrier. There can be many different kinds....beds (K1, gravel and sand,..etc.) that are static in run time and are fluidized to clean them. Other types may be a PITA to clean such as screens or layers of matting. I can not imagine someone having to try to clean a pile of matting layers every week. Open cell foam makes a GREAT barrier. The problems are in clogs in a heartbeat and is dang near impossible to clean.

The two keys then to a "good mechanical stage" are its effectiveness and the ease of cleaning it. One without the other is not worth much in the real world.

I would agree. But I would want two for redundancy. And for many in the hobby, the cost of RDFs is still prohibitive. But if cost is not the limit, it is very hard to beat an RDF that feeds a shower.

If you do the math for for 8k to 10k gallon pond for mechanical equipment plus beat filter for fine filter then the cost is almost the same as the RDF. Add two Cetus plus Advantage 15 or Ultima II bead fitler then it will put you in the mid to high 4K+.